Electrochemical selenium- and iodonium-initiated cyclisation of hydroxy-functionalised 1,4-dienes

• Philipp Röse,
• Steffen Emge,
• Jun-ichi Yoshida and
• Gerhard Hilt

Beilstein J. Org. Chem. 2015, 11, 174–183, doi:10.3762/bjoc.11.18

• alcohol functionality takes place. It is mentionable that under the reaction conditions no aromatic iodination could be observed. Next to sodium iodide other iodide sources such as KI, I2 or Bu4NI can be used, whereas applying other halogenides such as NaBr, Et4NBr or Bu4NCl led to a complex mixture of

Articulated rods – a novel class of molecular rods based on oligospiroketals (OSK)

• Pablo Wessig,
• Roswitha Merkel and
• Peter Müller

Beilstein J. Org. Chem. 2015, 11, 74–84, doi:10.3762/bjoc.11.11

• ). A similar behaviour is observed in the presence of the double-stranded lipid DOPC, which typically forms vesicles with membrane double layers. To determine the orientation of 32a in the membranes quenching experiments with KI were undertaken (for details see Supporting Information File 1). We found

• a rapid decrease of the pyrene fluorescence to ca. 50% at low KI concentrations whereas considerably higher KI concentrations were required to quench the fluorescence below 50%. This outcome clearly indicates that the AR is incorporated with a perpendicular orientation to the membrane surface

Copper-promoted hydration and annulation of 2-fluorophenylacetylene derivatives: from alkynes to benzo[b]furans and benzo[b]thiophenes

• Yibiao Li,
• Liang Cheng,
• Xiaohang Liu,
• Bin Li and
• Ning Sun

Beilstein J. Org. Chem. 2014, 10, 2886–2891, doi:10.3762/bjoc.10.305

• , the use of 0.2 equiv of KI as an additive afforded 2a in a satisfactory 95% yield (Table 1, entry 6). The base loading had a strong influence on the yield with 2 equiv KOH being the optimal amount (Table 1, entries 7 and 12). Further screening of bases did not lead to better yields and confirmed that

• -fluorophenylacetylene derivatives. Copper-promoted reaction of 2-fluorophenylacetylene derivatives to yield benzo[b]furans. Reaction conditions: Alkyne 1a (1.0 mmol), catalyst (10 mol %), KOH (2.0 mmol), H2O (1.5 mmol) and KI (0.2 mmol) in 3 mL of DMSO at 80 °C for 4–8 h; yields are given for isolated products. Copper

Thermal and oxidative stability of the Ocimum basilicum L. essential oil/β-cyclodextrin supramolecular system

• Daniel I. Hădărugă,
• Nicoleta G. Hădărugă,
• Corina I. Costescu,
• Ioan David and
• Alexandra T. Gruia

Beilstein J. Org. Chem. 2014, 10, 2809–2820, doi:10.3762/bjoc.10.298

• spectra with those from the NIST/EPA/NIH Mass Spectral Library 2.0 (2002). The second method involves comparison of the calculated Kovats index (KI) for some compounds with those previously determined by our research group. The KIs were obtained by interpolating the retention time (tR) of the compound in

• the KI versus tR graph obtained for the C8–C20 alkane standard mixture analyzed under the same conditions by GC–MS. Statistical analysis The β-CD encapsulation-competition data and the main descriptor indicating the hydrophobicity of the compounds (log P – the logarithm of 1-octanol/water partition

• (OM and OS); the encapsulation efficiency and hydrophobicity were the PCA variables). The GC–MS data (Kovats index – KI, relative concentrations – Area (%)) of the raw (B) and recovered from β-CD complex (B/β-CD) of O. basilicum L. essential oil, the relative encapsulation efficiency (E.E.) and the

Synthesis of nanodiamond derivatives carrying amino functions and quantification by a modified Kaiser test

• Gerald Jarre,
• Steffen Heyer,
• Elisabeth Memmel,
• Thomas Meinhardt and
• Anke Krueger

Beilstein J. Org. Chem. 2014, 10, 2729–2737, doi:10.3762/bjoc.10.288

• : positive result; b) left: control, control with premature addition of 60% ethanol solution (before solution has fully cooled down and colour has vanished). Synthesis of nanodiamond derivatives carrying primary amino groups. a) Δ, b) 18-crown-6, KI, c) BH3·THF, d) 4-aminobenzonitrile, isopentyl nitrite, e

Gold(I)-catalysed synthesis of a furan analogue of thiamine pyrophosphate

• Amjid Iqbal,
• El-Habib Sahraoui and
• Finian J. Leeper

Beilstein J. Org. Chem. 2014, 10, 2580–2585, doi:10.3762/bjoc.10.270

• very strong inhibitor, with a Ki value of 32.5 pM. It was also shown that the furan analogue of thiamine can be functionalised at the C-2 position, which will allow access to mimics of reaction intermediates of various ThDP-dependent enzymes. Keywords: furan synthesis; gold-catalysed cyclisation

• , which binds 25,000 times more strongly (Ki = 14 pM) than ThDP to PDC from Zymomonas mobilis (ZmPDC) and 500 times more strongly (Ki = 5 nM) to the E1 component of α-ketoglutarate dehydrogenase [10]. This extremely tight binding can be rationalised by the structural similarity between 2 and the ylid of

• . Two triazole analogues 3 (Ki = 20 pM) and 4 (Ki = 30 pM against ZmPDC) were synthesised in just four synthetic steps [12]. However, there is no possibility of attaching a substituent at the 2-position of the triazole to mimic enzymic reaction intermediates. Another analogue of ThDP 5 with a benzene

Towards the sequence-specific multivalent molecular recognition of cyclodextrin oligomers

• Michael Kurlemann and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2014, 10, 2428–2440, doi:10.3762/bjoc.10.253

• multivalent binding model gives effective molarities (EM) of 0.33 mM for the system 1/8 and 0.22 mM for the system 3/8 (Table 2). In combination with the intrinsic binding constants Ki of both systems the specific chelate cooperativities can be calculated by multiplication of EM and Ki. With these values a

• inclusion complex is formed first. In the second step the intramolecular complexation between the n-butyl moiety of 9 and the α-CD of 2, (Ki ≈ 102 M−1) has to appear to build a double stranded structure. Here again a negative chelate cooperativity is present (Ki·EM ≈ 0.03), preventing the intramolecular

• from the heterodivalent system 2/9 it is obvious that during the interaction between 5 and 12 first the complexation between the adamantane of 12 and the β-CD of 5 takes place. The following intramolecular complexation of one of the n-butyl moieties by one of the α-CD (Ki ≈ 102 M−1) does not occur due

Pyrrolidine nucleotide analogs with a tunable conformation

• Lenka Poštová Slavětínská,
• Dominik Rejman and
• Radek Pohl

Beilstein J. Org. Chem. 2014, 10, 1967–1980, doi:10.3762/bjoc.10.205

• ) – inhibitors of thymidine phosphorylase isolated from spontaneous lymphoma of SD rats (IC50 = 15 and 11 nM, respectively) [4], guanine derivative 5 – a potent inhibitor of human purine nucleoside phosphorylase PNP (Ki = 10 nM) [5], and finally guanine derivative 6 – exhibiting inhibitory activity against 6

Multicomponent reactions in nucleoside chemistry

• Mariola Koszytkowska-Stawińska and
• Włodzimierz Buchowicz

Beilstein J. Org. Chem. 2014, 10, 1706–1732, doi:10.3762/bjoc.10.179

• presence sodium acetate in dioxane at 100 °C. The compound was prepared on the 10 mg scale in 67% yield. In contrast to its (3R,4R)-enantiomer (not shown), compound (3S,4S)-23 showed inhibitory activity toward human purine nucleoside phosphorylase (PNP) with a slow-onset binding constant Ki* = 0.032 nM. In

Synthesis of the first examples of iminosugar clusters based on cyclopeptoid cores

• Mathieu L. Lepage,
• Alessandra Meli,
• Anne Bodlenner,
• Céline Tarnus,
• Francesco De Riccardis,
• Irene Izzo and
• Philippe Compain

Beilstein J. Org. Chem. 2014, 10, 1406–1412, doi:10.3762/bjoc.10.144

• inhibitory activity (Ki, μM) against jack bean α-mannosidase. Supporting Information Supporting Information File 48: Mannosidase inhibition assay procedures, synthesis and NMR spectra of all new compounds. Acknowledgements This work was supported by the Institut Universitaire de France (IUF), the CNRS (UMR

An economical and safe procedure to synthesize 2-hydroxy-4-pentynoic acid: A precursor towards ‘clickable’ biodegradable polylactide

• Quanxuan Zhang,
• Hong Ren and
• Gregory L. Baker

Beilstein J. Org. Chem. 2014, 10, 1365–1371, doi:10.3762/bjoc.10.139

• change of KI-starch test paper), which destroy product 1 during concentration and drying under vacuum. And neither addition of urea (reacting with HNO2 to release N2, CO2 and H2O) nor passing of crude product 1 through a short silica gel column can stop its decomposition. So three reductants were

Substitution effect and effect of axle’s flexibility at (pseudo-)rotaxanes

• Friedrich Malberg,
• Jan Gerit Brandenburg,
• Werner Reckien,
• Oldamur Hollóczki,
• Stefan Grimme and
• Barbara Kirchner

Beilstein J. Org. Chem. 2014, 10, 1299–1307, doi:10.3762/bjoc.10.131

• differences such as substitution or dealkylation. Acknowledgements We would like to thank the DFG in the framework of the collaborative research center SFB 624 “Templates” at the University of Bonn for the funding of this research. Furthermore, the financial support of the DFG project KI 768/7-1 is gratefully

Staudinger ligation towards cyclodextrin dimers in aqueous/organic media. Synthesis, conformations and guest-encapsulation ability

• Malamatenia D. Manouilidou,
• Yannis G. Lazarou,
• Irene M. Mavridis and
• Konstantina Yannakopoulou

Beilstein J. Org. Chem. 2014, 10, 774–783, doi:10.3762/bjoc.10.73

• are located inside the cavity. (a) i) HCl, NaNO2/H2O, then KI/H2O, 58%, ii) Ph2PH, Pd(OAc)2, Et3N, MeOH, 48%; (b) i) CH3COOH, H2SO4, CCl4, I2, IO3, 85 °C, 4 h, exclusion of light, 70%; ii) C5H5N, H2O, KMnO4, reflux, 24 h, exclusion of light, 55%; iii) KOH in water (10% w/v), KMnO4, reflux, 4 h

Phosphinate-containing heterocycles: A mini-review

• Olivier Berger and
• Jean-Luc Montchamp

Beilstein J. Org. Chem. 2014, 10, 732–740, doi:10.3762/bjoc.10.67

• transcarbamoylase (ATCase). 5-Membered 26 was completely inactive, whereas 6-membered 29 showed modest activity (Ki = 1 μM, 63 times less active than phosphonic acid N-phosphonacetyl-L-aspartate PALA, Ki = 16 nM). 1,3-Azaphosphorines and 1,3-azaphospholidines Several 1,3-azaphosphorines and 1,3-azaphospholidines

Preparation of new alkyne-modified ansamitocins by mutasynthesis

• Kirsten Harmrolfs,
• Lena Mancuso,
• Binia Drung,
• Florenz Sasse and
• Andreas Kirschning

Beilstein J. Org. Chem. 2014, 10, 535–543, doi:10.3762/bjoc.10.49

• metabolites and copies of 1H and 13C NMR spectra. Supporting Information File 182: Additional experimental details and NMR spectra. Acknowledgements This work was supported by the Deutsche Forschungsgemeinschaft (grant Ki-397, 13-1) and the Fonds der Chemischen Industrie.

Deoxygenative gem-difluoroolefination of carbonyl compounds with (chlorodifluoromethyl)trimethylsilane and triphenylphosphine

• Fei Wang,
• Lingchun Li,
• Chuanfa Ni and
• Jinbo Hu

Beilstein J. Org. Chem. 2014, 10, 344–351, doi:10.3762/bjoc.10.32

• examples include using bis(trifluoromethyl)mercury (Hg(CF3)2) under the promotion of NaI (Scheme 1, reaction 3) [24] and using methyl 2,2-difluoro-2-(fluorosulfonyl)acetate (MDFA) under the promotion of KI (Scheme 1, reaction 4) [25]. Our group has focused on the development and application of new

Carbenoid-mediated nucleophilic “hydrolysis” of 2-(dichloromethylidene)-1,1,3,3-tetramethylindane with DMSO participation, affording access to one-sidedly overcrowded ketone and bromoalkene descendants^§

• Rudolf Knorr,
• Thomas Menke,
• Johannes Freudenreich and
• Claudio Pires

Beilstein J. Org. Chem. 2014, 10, 307–315, doi:10.3762/bjoc.10.28

• NaOCl solution in an amount that sufficed for showing a positive potassium iodide/starch test for 30 min, at which time this residual NaOCl was forthwith destroyed by solid NaHSO3 that had to be added until the KI/starch test became negative. (KMnO4 in place of NaOCl was found to decompose 17.) The

Synthesis, characterization and initial evaluation of 5-nitro-1-(trifluoromethyl)-3H-1λ³,2-benziodaoxol-3-one

• Nico Santschi,
• Roman C. Sarott,
• Elisabeth Otth,
• Reinhard Kissner and
• Antonio Togni

Beilstein J. Org. Chem. 2014, 10, 1–6, doi:10.3762/bjoc.10.1

• and the grey precipitate was filtered off and washed with copious amounts of water. Then, the filtrate was suspended in water (100 mL), heated to 100 °C and treated with a solution of KI (8.5 g, 51.2 mmol, 1.3 equiv) and H2SO4 (5 drops) in water (10 mL) over the course of 1 h. Finally, the brown

Studies toward bivalent κ opioids derived from salvinorin A: heteromethylation of the furan ring reduces affinity

• Thomas A. Munro,
• Wei Xu,
• Douglas M. Ho,
• Lee-Yuan Liu-Chen and
• Bruce M. Cohen

Beilstein J. Org. Chem. 2013, 9, 2916–2924, doi:10.3762/bjoc.9.328

• caused ≥50% inhibition of [3H]diprenorphine binding. The Ki of 4 was 110 nM (Table 1), a substantial reduction in affinity relative to 1. None of these compounds showed detectable affinity for µ- or δ-OR (Ki > 1 μM in all cases). Thus, 4 showed modest affinity and selectivity for κ-OR, while 2, 3 and 5

• showed no affinity for any opioid receptor. Follow-up testing in the [35S]GTPγS functional assay demonstrated that 4 was an agonist less potent than 1 at κ-OR, but giving an equal maximal response (Table 1). (2-Hydroxyethoxy)methyl ether 6 showed high affinity for κ-OR, but not for µ- or δ-OR (Ki > 1 μM

Stereoselectively fluorinated N-heterocycles: a brief survey

• Xiang-Guo Hu and
• Luke Hunter

Beilstein J. Org. Chem. 2013, 9, 2696–2708, doi:10.3762/bjoc.9.306

• oxocarbenium ion, the iminosugars 31 and 41–44 (Figure 11) must bear a positive charge, and since the pKaH values vary considerably amongst the different derivatives, it follows that each derivative has a different “optimal” pH for maximal inhibitory potency. This explains why the Ki values in Figure 11 do not

• seem to follow a clear trend: the quoted Ki values were all measured at the same pH, whereas it would be more revealing to consider the Ki of each molecule at its “optimal” pH. This is a very interesting situation, because it opens up the possibility of developing drugs that are selective for

The myxocoumarins A and B from Stigmatella aurantiaca strain MYX-030

• Tobias A. M. Gulder,
• Snežana Neff,
• Traugott Schüz,
• Tammo Winkler,
• René Gees and
• Bettina Böhlendorf

Beilstein J. Org. Chem. 2013, 9, 2579–2585, doi:10.3762/bjoc.9.293

• CaCl2, 1 mL mineral solution (consisting of 0.1 g H3BO3, 5 g FeSO4·7H2O, 0.05 g KI, 2 g CoCl2·6H2O, 0.2 g CuSO4·5H2O, 2 g MnCl2·4H2O, 4 g ZnSO4·7H2O, 1 g 95% H2SO4 for 1 L solution), 10 mL vitamin solution (consisting of 10 mg folic acid, 6 mg biotin, 0.2 g p-aminobenzoic acid, 1 g thiamin·HCl, 1.2 g

Structure of 1,5-benzodiazepinones in the solid state and in solution: Effect of the fluorination in the six-membered ring

• Marta Pérez-Torralba,
• Rosa M. Claramunt,
• M. Ángeles García,
• Concepción López,
• M. Carmen Torralba,
• M. Rosario Torres,
• Ibon Alkorta and
• José Elguero

Beilstein J. Org. Chem. 2013, 9, 2156–2167, doi:10.3762/bjoc.9.253

• . 6,7,8,9-Tetrafluoro-1,4-dimethyl-1,3-dihydro-2H-1,5-benzodiazepin-2-one (2). A solution of 1 (0.40 g, 1.62 mmol) in DMF (2 mL) was heated at 110 °C in the presence of iodomethane (0.11 mL, 1.79 mmol), K2CO3 (0.27 g, 1.95 mmol) and a catalytic quantity of KI for 90 min. The mixture was cooled, treated with

Selective copper(II) acetate and potassium iodide catalyzed oxidation of aminals to dihydroquinazoline and quinazolinone alkaloids

• Matthew T. Richers,
• Chenfei Zhao and
• Daniel Seidel

Beilstein J. Org. Chem. 2013, 9, 1194–1201, doi:10.3762/bjoc.9.135

• aminals. Here we present catalytic methods for the synthesis of both these compound classes from aminals using Cu(OAc)2/O2/AcOH and KI/TBHP systems, respectively. Results and Discussion Copper-catalyzed oxidations of aminals to dihydroquinazolines Copper-catalyzed oxidation reactions have received a great

• did not reach completion after 3 days. The attenuated reactivity of aminal 19 is most likely the result of the decreased electron density on the anilinic nitrogen. KI-catalyzed oxidations of aminals to quinazolinones Different conditions for the direct catalytic oxidation of aminals to quinazolinones

• ion. However, the major product from this reaction was identified to be 31, the apparent product of iminium hydrolysis. Conclusion We have demonstrated that quinazoline alkaloids and their analogues can be synthesized from aminals by using Cu(OAc)2/O2/AcOH and KI/TBHP catalyst systems. The use of

Efficient regio- and stereoselective access to novel fluorinated β-aminocyclohexanecarboxylates

• Loránd Kiss,
• Melinda Nonn,
• Reijo Sillanpää,
• Santos Fustero and
• Ferenc Fülöp

Beilstein J. Org. Chem. 2013, 9, 1164–1169, doi:10.3762/bjoc.9.130

• ester 1 is treated with KI/I2 in H2O/CH2Cl2, which affords iodooxazinone derivative 2 stereo- and regioselectively (Scheme 1, Figure 1). Next, compound 2 is transformed to 3 by amide N-Boc protection with Boc2O and 4-dimethylaminopyridine (DMAP) in THF. Removal of the iodine from the cyclohexane

• regio- and stereoselective iodooxazine formation with KI/I2 to give compound 11 (Scheme 3). N-Protection of 11, followed by reductive deiodination, proceeded via 12 (Figure 3) to afford ester 13. Opening of the heterocyclic ring with NaOEt in EtOH at 0 °C furnished 4-hydroxylated amino ester 14, a

Tandem dinucleophilic cyclization of cyclohexane-1,3-diones with pyridinium salts

• Mostafa Kiamehr,
• Firouz Matloubi Moghaddam,
• Satenik Mkrtchyan,
• Volodymyr Semeniuchenko,
• Linda Supe,
• Alexander Villinger,
• Peter Langer and
• Viktor O. Iaroshenko

Beilstein J. Org. Chem. 2013, 9, 1119–1126, doi:10.3762/bjoc.9.124

• about reaction products is limited by the obscure structure of the real reaction product. In fact the reaction of pyridinium salt 2a with cyclic 1,3-diketones in the presence of either K2CO3 or DIPEA/KI yields an orange precipitate in acetonitrile. Redissolved in DMSO-d6, this precipitate gave rise to

• is quickly decomposed by silica gel liberating the desired product 3a or 6a, which was finally eluted from silica. The formation of a precipitate must be a driving force of the reaction promoted by DIPEA/KI (see Supporting Information File 2, thermodynamic analysis). The reaction starts with 1,3